The present invention pertains to linear electric motors used in powering transportation vehicles and trains of vehicles, and more particularly pertains to features allowing direct use of pulsating current to achieve planned vehicle speed and power.
Various embodiments of the present invention allow reduction of the amount of non-ferrous metal required per mile of road; reduction of required vehicle weight so as to allow better performance for a given input power, and reduction of overall system cost.
Linear electric transportation motors have motor parts on both the vehicle (vehicle parts) and the road (road parts). Electric currents in the vehicle parts and road parts interract to produce both propulsion and braking force for acceleration and deceleration of the vehicle.
Previously known linear motors include the linear induction motor, termed the LIM, the linear synchronous motor, termed the LSM, and the segmented rail phased induction motor, termed the SERAPHIM. LIM and SERAPHIM motors have vehicle parts that are directly powered, and road parts that are inductively powered. The LSM has directly powered road parts and has superconducting magnets for vehicle parts.
In order for either the LIM or SERAPHIM system to employ utility power, there must be sliding electrical contact with the power line, which may be impractical for high speed, and also considerable power conditioning equipment on the vehicle.
Although an LSM system requires no sliding contacts to use utility power, it requires expensive stationary power conditioning equipment at many sites along the road, and there are traffic restrictions between substations.
And these previously known linear motor systems require use of such large amounts of nonferrous metal, copper or aluminum, as to be cost-prohibitive for large scale operation.
All the embodiments of the present invention described below, require use of far less power conditioning equipment and substantially less nonferrous metals, than required for use of the previously known linear motor systems. Some embodiments of the present invention use motor parts similar to those of SERAPHIM, following applicant's and Barry Marder's inventions described in previous U.S. Pat. Nos. 5,552,649 and 6,445,092, the specification disclosures of which patents are hereby incorporated herein by reference in their entireties. However, the motors of the present invention are not “segmented-rail phased induction motors.” Only one embodiment of the present invention uses inductively reactive parts, and they are used on the vehicle instead of in a segmented rail.
All below-described embodiments of the present invention require use of far fewer road parts per mile than in previous linear motor systems, and some allow direct use of alternating current of constant frequency for all vehicle speeds.
Another advantage of one embodiment of the present invention, is that it would allow interchangeable use of a linear motor locomotive and a conventional one, on an existing conventional railroad; whereas use of previously known linear motors would require extensive design changes in railroads and rolling stock, precluding conventional use.
Previous linear motors use a separate “rail” for motor parts in addition to a road used for vehicle suspension by wheels or by magnetic force. If one structure could serve both functions a significant cost reduction could result. One embodiment of the present invention meets this need by incorporating the road parts of the linear motor in a thin roadway with flat vertical sides, onto which the vehicle wheels are compressed, which roadway is mounted directly above an elevated vehicle, as disclosed in applicant's invention claimed in U.S. Pat. No. 6,388,117B1, the specification disclosure of which patent is incorporated herein by reference in its entirety.
It is not the intent of this application, by stating that certain embodiments of the present invention are suited to certain purposes or to dealing with certain problems, to necessarily limit the scope of the invention to only embodiments which are useful for said purposes or problems; it is instead the intent that the scope of the invention be determined by the claims as more fully stated below.